The overall objective of this project was to study an animal model system using chemically induced tumors in inbred rats to determine if a reliable immunological assay can be devised to detect tumor specific antigens. The tumors studied were transplantable Morris hepatomas (7777, 5123Tc, 3924a). The growth characteristics of the tumor lines was established. The threshold intramuscular dose of tumor cells was 1x10 to the 5th power for all tumor lines. Metastatic patterns varied greatly with lung metastatic lesions developing first in tumor line 5123Tc. Tumor specific transplantation antigens were demonstrated for all of the tumor lines following amputation of an intramuscular tumor or following immunization with X-irradiated tumor cells. Tumor antigen extracts were made using the previously described M3 KCl extraction method. Tumor antiserum was prepared by the immunization of rabbits with tumor cells inoculated subcutaneously. Follow absorption of this antiserum with normal rat serum, a mono-specific antiserum was obtained which showed a precipitin line by double-diffusion-in-agar testing to the M3 KCl tumor extracts. Antiserum obtained from animals immunized to tumor line 3924a showed a precipitin line with 3924a extract and identity with absorbed rabbit anti-serum to 3924a tumor cells. Immunoprotection studies are currently being conducted using the tumor extracts to immunize rats against a subsequent intramuscular tumor challenge. We hope to further purify and characterize the tumor antigen extract by physiochemical means and subsequently develop a highly sensitive tumor specific antigen detection system. When this is done, we will study serum samples from animals at various stages of tumor development from immunized animals or animals which may have "enhanced" tumor growth.